Light-emitting diodes (LED) have such advantages as being power-saving, producing little pollution, and having a small volume, a long life-time (hundred thousand hours), a fast response time, a high reliability, and a large module flexibility. As a result, LEDs are widely applied in technical fields. With the currently progress being made in technological developments, the efficiency and brightness of LEDs are continuously being enhanced, so that the range of possible applications is large enough to cover applications such as the backlight module of a display and the light source in a vehicle. In the near future, it will be possible for LEDs to replace fluorescent lamps, becoming the next-generation light source. Furthermore, LEDs with high power and high brightness are becoming the mainstream of future development, and the demands upon them are gradually increasing. Conventional thermosetting epoxy molding compounds (EMC) are mainly utilized in semiconductor IC packaging, such as packaging, protecting, and encapsulating chip circuits and lead pins in the front end-of-line and related materials to avoid external damage and influence from the outside environment. Almost all of the epoxy resins and curing agents of the EMC are multifunctional solid materials, which are ground and dry-mixed, and then blended with a large quantity of inorganic powders by using blending equipment (e.g. bi-axial blender). As such, a thermosetting and transfer molding resin composition (e.g. EMC) with a uniform dispersion, tunable process flowability, and fast cure molding is obtained. However, these resin and curing agent materials are opaque, and as such that they are limited to applications in semiconductor IC packaging, and cannot be used in an optical application requiring transparency, such as in LED white reflective EMC material.
The conventional LED backlight module and LED package device for general illumination have been developed to meet such requirements as high brightness and high power. A thermoplastic resin polyphthalamide (PPA) of a reflective cup for conventional PLCC LEDs cannot be applied in high-power PLCC LEDs due to its low photo thermal resistance and easy yellowing. In recent years, the thermoplastic material also includes a novel injection molding material PCT (polyester type), but it still fails to efficiently improve upon the thermoplastic material properties of low photo thermal resistance and easy yellowing.
Accordingly, a thermosetting EMC white reflective material with a higher thermal and photo resistance is called for to meet the material requirements (photo and thermal stability) of high-power LED devices to improve the reliability of the LED package device.